Candida parapsilosis에 의한 Xylitol 생성시 포도당의 영향

오덕근,김종화 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.2

Candida parapsilosis TACC 21019 돌연변이주를 사용하여 xylose 배지에서 배양시 glucose 첨가가 xylitol 생산에 미치는 영향을 조사하였다. Glucose를 첨가한 배지에서 glucose 함량이 높을수록 xylitol 생성량은 감소하였지만 ethanol과 glycerol 양은 증가하여 xylose 10 g/l와 glucose 40 g/l일 때 최대값 각각 21.5g/l, 3.6g/l을 나타내었다. Glucose만 존재하는 배지에서는 xylitol이 전혀 생성되지 않았고 이 결과는 glucose에서는 xylitol이 생성되지 않는다는 것을 의미한다. Xylose에 대한 glucose의 비율을 증가시켜며 배양한 결과 glucose 비율이 높을수록 xylose를 xylitol로 전환하는 xylose reductase 역가가 감소하였다. Xylitol을 xylulose로 전환(xylulose는 세포 구성성분으로 전환됨)하는 xylitol dehydrogenase의 역가는 첨가된 glucose의 양에 상관없이 xylose 이용하는 동안하는 일정하여 glucose 첨가가 세포성장에 미치는 영향은 거의 보여주지 않았다. Xylose로 부터 xylitol 생성시 glucose의 저해효과를 방지하기 위하여 glucose를 낮은 수준으로 유지되게 첨가하는 실험을 수행하였다. 그 결과 부산물인 ethanol과 glycerol 양이 감소되었고 이용된 xylose에 대한 생성된 xylitol의 수율은 xylose 만으로 배양할 때와 거의 같은 수준을 보여주었다. 그러나, xylitol 생성시 전제창(xylose와 glucose)에 대한 xylitol 생성 기여는 전혀 없었다. 그러므로 glucose가 없는 고농도 xylose 배지로 xylitol 생산을 시도하였다. Xylose 농도 300 g/l의 배지에서 배양시 272시간에서 xylose가 모두 소모 되었으며 최종 xylitol의 농도는 242 g/l이었고 이것은 xylose에 대한 xylitol의 생산수율 80.7%에 해당된 것이다. Effect of glucose addition to xylose medium on xylitol production was investigated by using Candida parapsilosis TACC 21019 mutant. With increasing the ratio of glucose to xylose in total amount of 50 g/1 as g/l as glucose and/or xylose, xylitol production was decreased but ethanol and glycerol production were increased. Ethanol and glycerol concentration were maxmum in 10 g/l of xylose and 40 g/l of glucose medium 21.5 g/ㅣand 3.6 g/l, respectively. No xylitol was formed in glucose medium without xylose because xylitol could be not produced from glucose. With increasing the ratio of glucose to xylose, the activity of xylose reductase which converted xylose to xylitol were decreased. The activities of xylitol dehydrogenase which converted xylitol to xylulose and then cell materials were found to be constant regardless of the ratio of glucose to xylose. This results indicated that glucose addition to xylose medium on cell growth was not affected. In order to prevent the inhibitory effect of glucose on xylitol production, glucose in a fermentor was fed with low concentration and then ethanol and glycerol was critically decreased and the xylitol yield from xylose of the culture with glucose feeding was recovered the almost same as that with only 50 g/l xylose. However, the xylitol yield from total sugars (xylose and glucose) was decreased and glucose was not contributed to xylitol production. Therefore, the fermentation at high concentration of xylose without glucose was carried out. A final xylitol concentration of 242 g/l which correspnding 80.7% of xylitol yield was obtained from 300 g/l xylose for 273 hours.

Candida parapsilosis 돌연변이주에 의한 Xylitol 생산의 배지조건 최적화

오덕근,윤상현,김정민,김상용,김정회 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.4

Candida parapsilosis ATCC 22019 돌연변이주를 사용하여 xylitol 생산에 영향을 주는 배지성분의 최적화를 수행하였다. Xylose 50 g/l 배지에서 여러 가지 질소원이 xylitol 생산에 미치는 영향을 살펴본 결과 xylitol 생산에는 무기질소원으로는 (NH_4)_2SO_4가 좋았으며 유기질소원으로는 yeast extract가 가장 좋았다. 무기염으로 KH_2PO_4 ad MgSO_4·7H_2O를 선정하여 최적화를 수행하였고 그 결과 최적배지로 xylose of 50 g/l, yeast extract of 5 g/l, (NH_4)_2SO_4 of 5 g/l, KH_2PO_4 of 5 g/l, MgSO_4·7H_2O of 0.2 g/l로 결정하였다. 최적배지를 사용하여 발효조에서 64시간 배양하였을 때 xylose는 모두 소모되었으며 최종 균체농도와 xylitol 생산량은 각각 7.6 g/l와 37 g/l을 얻었다. 이때, xylose로 부터 xylitol의 전환수율 74%이었고, xylitol의 생산성은 0.58 g/l-hr이었다. 최적배지에서 총 첨가된 xylose에 대한 xylitol의 생산수율 80.7%에 해당되었고 xylitol의 생산성은 0.94g/l-hr에 해당되었다. Medium optimization for xylitol production from xylose by Candida parapsilosis ATCC 22019 mutant was performed. Effect of various nitrogen sources on xylitol production was investigatied. Of inorganic nitrogenous compounds, ammonium sulfate was effective for xylitol production and yeast extract was the most suitable orangic nitrogen nutrient for enhancement of xylitol production. Effect of inorganic salts such as KH_2PO_4 ad MgSO_4·7H_2O on xylitol production was also studied. Optimal medium was selected as xylose of 50 g/l, yeast extract of 5 g/l, (NH_4)_2SO_4 of 5 g/l, KH_2PO_4 of 5 g/l, MgSO_4·7H_2O of 0.2 g/l. In a fermentor by using the optimal medium, a final xylitol concentration of 37 g/l could be obtained from 50 g/l of xylose with a xylitol yield of 74% and a xylitol productivity of 0.58 g/l-hr. At 300 g/l xylose, fermentation was also carried out and then a final xylitol concentration of 242 g/l was obtained at 272 hours. It was corresponding to xylitol yield of 80.7% and xylitol productivity of 0.58 g/l-hr.

FH 통신에서의 안정된 주파수 합성기의 개발

정명덕,김민호,변건식 동아대학교 공과대학 부설 한국자원개발연구소 1995 硏究報告 Vol.19 No.1

For FH-SS communication, We discussed the method of indirect synthesizer in several methods. The problem of single frequency synthesizer using with PLL is a varied coefficient value of damping factor in frequency hopping time, which is caused unstable frequency. So, for stable frequency synthesizer, a coefficient of damping factor must be optimized and synthesized to be removed excessive response time. In this paper, we studied FH using with 2 loop frequency synthesizer which takes stable frequency, we made up simulator and had a good performance(real time speed).

질소원 제한 상태에서의 다당류, 메틸란 발효에 관한 동력학적 모사

오덕근 又石大學校 1996 論文集 Vol.18 No.-

Model equations were proposed to illustrate the kinetics of polysaccharide, methylan, fermentation under nitrogen limitation. The proposed equations appeared to explain well the growth characteristics that Methylobacterium organophilum grew continuously even after the depletion of ammonium ion supplied to the medium and showed the good agreement with the experimental data on the changes of cell growth, methylan production and ammonium ion concentration during the culture. The application of kinetic equations were carried out in the various concentration of ammonium ion with estimated parameters at 0.3 g/1 of ammonium ion. Model equations could satisfactorily fit the experimental data for the low concentration of ammonium ion within 0.3 g/1. However, product parameters of 0.3 g/1 ammonium ion could not apply to simulate the experimental data of methylan production for the high concentration of ammonium ion beyond 0.45 g/1 because exess ammonium ions inhibited methylan production. Therefore, methylan production for the high concentration of ammonium ion could be simulated by using product parameters in each culture. Effect of ammonium ion concentration on product parameters was investigated. The non-growth associated product parameter was very small and almost constant and, growth associated product parameter was constant within 0.3 g/1 of ammonium ion but decreased beyond 0.45 g/1 of ammonium ion.

CPSO를 이용한 GPS 위성 데이터 추출회로 개발

김성곤,최희주,정명덕,변건식 東亞大學校 附設 情報通信硏究所 1998 情報通信硏究所論文誌 Vol.6 No.1

A synchronization is important element not only wire communication but also wireless communication. Especially, In SS(Spread Spectrum) communication method used GPS(Global Positioning System) synchronization is more important. A synchronous oscillator(SO) is a network which synchronizes, tracks, filter, amplifies and divides (if necessary) in a single process. Without an input signal, the SO is a free-running oscillator, oscillating at a frequency w??, but phase changes 180。 within tracking range of SO. Therefore CPSO was used for this problem. The coherent phase synchronous oscillator(CPSO) is created by adding two external loops to the SO and has a wider tracking bandwidth and a zero-offset phase response (coherent) while maintaining the SO properties of high signal-to-rejection and fast frequency acquisition times. Therefore phase between input signal and output signal is synchronized. In this paper, GPS data recovery circuit has applied CPSO using front reference characters and has certified and excellent data recovery capability.

검사/계측시스템의 능력분석을 포함한 비공정능력지수의 개발과 적용

민성진,김계완,류정현,윤덕균 한국품질경영학회 2002 품질경영학회지 Vol.30 No.1

This paper presents a process incapability index to provide manager with various information of process and to reduce cost. The introduced process incapability indices indicate information about mean and variance of manufacturing process and variance of inspection process to evaluate process capability using ratio of variance and difference between target and mean to specification. This model can be used by the scale of six sigma management.

Biotechnology Tools for the Industrial Biosynthesis of Rare Monosaccharides

Deok-Kun OH 한국생물공학회 2017 한국생물공학회 학술대회 Vol.2017 No.10

L-Ribose production from L-arabinose using L-arabinose isomerase and mannose-6-phosphate isomerase from Geobacillus thermodenitrificans

Deok-Kun Oh 한국당과학회 2009 한국당과학회 학술대회 Vol.2009 No.1

The uncharacterized gene previously proposed as a mannose-6-phosphate isomerase from Geobacillus thermodenitrificans was cloned and expressed in E scherichia coli. The maximal activity of the recombinant enzyme was observed at pH 7.0 and 70ºC in the presence of 1 mM Co2+. The isomerization activity was specific for aldose substrates possessing hydroxyl groups oriented in the same direction at the C2 and C3 positions,such as the D- and L-forms of ribose, lyxose, talose, mannose, and allose. The enzyme exhibited the highest activity for L-ribulose among all pentoses and hexoses. Thus, L-ribose, as a potential starting material for many L-nucleoside-based pharmaceutical compounds, was produced at 213 g/liter from 300 g/liter L-ribulose by mannose-6-phosphate isomerase at 70ºC for 3 h, with a conversion yield of 71 % and a volumetric productivity of 71 g liter–1 h–1. Two enzymes of L-arabinose isomerase and mannose-6-phosphate isomerase from G. thermodenitrificans produced 118 g/liter L-ribose from 500 g/liter L-arabinose at pH 7.0, 70ºC, and 1 mM Co2+ for 3 h, with a conversion yield of 23.6 % and a volumetric productivity of 39.3 g liter–1 h–1.

Effect of Ammonium Ion on the Production of a Polysaccharide, Methylan from Methanol by Methylobacterium organophilum

Deok-Kun Oh(오덕근),Hyun-Soo Lim(임현수),Jung-Hoe Kim(김정희) 한국생물공학회 1995 KSBB Journal Vol.10 No.2

STUDIES ON THE GENTAMICIN FERMENTATION BY MICROMONOSPORA PURPUREA

Deok Kun Oh,Young Je Cho,Nai Houn Park,Jae Heung Lee,Moo Young Yoo 한국생물공학회 1987 KSBB Journal Vol.1 No.2